The availability of mineral nitrogen in a wheat soil from southern New South Wales

1962 ◽  
Vol 2 (6) ◽  
pp. 185 ◽  
Author(s):  
RR Storrier

In a red-brown earth soil from Wagga Wagga the fluctuations in the level of mineral nitrogen (ammonia plus nitrate-nitrogen) and its availability to wheat under growing period rainfalls of 6 inches and 16 inches were studied. Ammonia-nitrogen did not exceed 8 lb nitrogen per acre 6 inches but showed statistically significant short term fluctuations. Mineral nitrogen decreased steadily from the 4-5 leaf stage of plant growth, reaching minimum values in the ear-emergence period when a temporary nitrogen deficiency occurred. Following rainfalls of about one inch or more, conditions favoured biological activity and nitrogen was mineralized, absorbed by the crop and/or leached down the profile. In one season a release of mineral nitrogen about two weeks before flowering contributed an estimated 20-30 per cent of the total nitrogen uptake of the crop. Nitrogen uptake by the wheat crop ceased after flowering and subsequent changes in mineral nitrogen level reflect the net result of mineralization and demineralization processes, and nitrogen uptake by weeds, particularly skeleton weed. Absorption of nitrogen from the profile depended upon seasonal conditions, with the surface 18 inches suppling the greater part of the nitrogen absorbed by the crop. This indicates the need to sample regularly to at least a depth of 18 inches, particularly during the period from 4-5 leaf to flowering, when studying the relation between mineral nitrogen and crop growth. The data suggest that the response of wheat, as measured by grain yield and protein content, to the higher levels of mineral nitrogen in the improved soils of southern New South Wales is determined by soil moisture levels, particularly in the post-flowering period.

1986 ◽  
Vol 26 (6) ◽  
pp. 709 ◽  
Author(s):  
AC Taylor ◽  
WJ Lill

Regular hand-weeding was undertaken in experiments located in 167 wheat crops in southern New South Wales from 1967 to 1970 to quantify the effect of weeds on 10 wheat attributes at flowering or maturity. Short annual grasses, skeleton weed, wild oats and annual legumes were the most widespread weeds, all of which tended to occur in mixed stands. At wheat flowering, over all sites, wheat DM, nitrogen concentration, nitrogen uptake, phosphorus uptake and number of ears were increased (P< 0.05) by 11.2, 3.3, 14.4, 13.6 and 7.8%, respectively by weeding; wheat phosphorus concentrations did not respond to weeding. At maturity, grain yield and nitrogen yield increased after weeding (P< 0.05) by 17.3 and 1 7.0%, respectively, but grain protein and kernel weight did not respond to weeding. Regression procedures were used to relate wheat responses to total weed DM and the DM of 8 weed classes. At flowering, for every 100 g of DM removed, wheat DM, nitrogen uptake, phosphorus uptake and ear number increased by 52.3 g m-2, 958 mg m-2, 92.6 mg m-2and 18.7 m-2, respectively. At maturity, grain yield and grain nitrogen yield increased by 31.9 g m-2 and 665 mg m-2, respectively, for every 100g m-2 of weed DM present at flowering. The regressions also showed that, at both flowering and maturity, fumitory, annual grasses and sundry weeds (a group made up of weeds not sufficiently widespread to consider separately) appeared to be the most aggressive weeds. Consideration of standardised responses of the wheat attributes increased by weeding showed that they all responded similarly when corrected for scale of measurement.


1988 ◽  
Vol 28 (2) ◽  
pp. 215
Author(s):  
AC Taylor ◽  
WJ Lill ◽  
AA McNeill

Dry matter and nitrogen uptake of wheat tops at flowering, dry matter and nitrogen of wheat grain at maturity, and soil mineral nitrogen (0-90 cm) at sowing and flowering, were measured at 68 sites (1 experiment per site in 5 Shires) in southern New South Wales to test the hypotheses that: (i) mineral nitrogen below 30 cm would improve the prediction of wheat yields, (ii) soil mineral nitrogen would be better indicated by wheat yields at flowering than those at maturity, and (iii) soil mineral nitrogen would be better indicated by nitrogen uptake by wheat than by dry matter yields. Mineral nitrogen concentrations in soil at depths greater than 30 cm did not improve the prediction of wheat attributes, but hypotheses (ii) and (iii) were validated. Curvilinear regressions, significant (P< 0.05) on 2 occasions, were not important in this study. The best regression of wheat dry matter at flowering against soil mineral nitrogen at sowing was a single straight line, but the best models for the other 3 wheat variables were all bilinear. The best of the latter related the uptake of nitrogen by wheat at flowering to mineral nitrogen in the soil at sowing as follows: FNUH = (31.6 � 5.9) + (0.892 � 0.110) TMNS30 and FNUL = (9.7 � 7.3) + (0.892 � 0.110) TMNS30 where FNUH is nitrogen uptake by wheat at flowering (kg/ha) in 1960, 1964 and 1966 (when Shire wheat yields were above the Shire's long term average), FNUL is nitrogen uptake by wheat at flowering (kg/ha) in 1961, 1965 and 1974 (when Shire wheat yields were below the Shire's long term average), and TMNS30 is total mineral nitrogen (0-30 cm) (kg/ha) at sowing.


1965 ◽  
Vol 5 (18) ◽  
pp. 323 ◽  
Author(s):  
RR Storrier

The changes in nitrogen concentration in the profile of a red brown earth soil, containing the equivalent of 160 lb mineral nitrogen per acre 18 inches at sowing, and to which ammonium sulphate at 0, 50, 100, and 150 lb nitrogen an acre had been added in early July, were measured for two seasons. A slow rate of nitrification resulted in the presence of high concentrations of residual ammonia-nitrogen 33 months later, equivalent to 55 and 30 per cent of the nitrogen added at the highest rate in fallowed and cropped treatments respectively. This residual ammonia-nitrogen persisted until the spring of the second season, a period of 13 months. Nitrogen was leached into the deeper subsoil, in the autumn and winter, when soil moisture was high and rain frequent. This leached nitrogen was retained in the surface 30 inches of the soil and subsequently taken up by the wheat crop. This uptake was responsible for differences in mineral nitrogen concentration between fallowed and cropped plots of approximately 82 and 96 per cent in the 0-18 inch and 0-30 inch depths respectively. It is suggested that leaching in low fertility soils, following heavy autumn and winter rains, could result in short term nitrogen deficiencies for crops in the Wagga Wagga region.


2006 ◽  
Vol 12 (2) ◽  
pp. 140 ◽  
Author(s):  
Michael F. Braby ◽  
Ted D. Edwards

Thirty-three species of butterflies are recorded from the Griffith district in the semi-arid zone of inland southern New South Wales. The butterfly community comprises the following structure: 19 species (58%) are resident; 7 (21 %) are regular immigrants; 2 (6%) are irregular immigrants; 5 (15%) are vagrants. Except for a few migratory species, most occur in relatively low abundance. Lack of similar studies elsewhere in western New South Wales precludes generalizations regarding the species richness, composition and structure of semi-arid butterfly communities. Comparison of the butterfly fauna with that from five other inland regions on the slopes and foothills of the Great Diving Range, revealed that the Griffith district is most similar in species richness and composition to that of Deniliquin and to a lesser extent Wagga Wagga and Cowra in the south, than with two regions in the higher summer rainfall area of the north of the State (Coonabarabran-Mendooran, Narrabri-Bellata). Overall, the butterfly fauna of inland New South Wales (total of 73 species, of which 49 occur in the southern regions) is depauperate compared with that recorded from the coastal/subcoastal areas east of the Great Dividing Range. Attention is drawn to the conservation significance of several vegetation types and habitat remnants in the Griffith district. Much of the native vegetation in the district has been extensively modified since European settlement due to excessive clearing for agriculture, resulting in a highly fragmented landscape for the conservation of native flora and fauna. With the exception of the lycaenid Candalides hyacinthinus Simplex, which is considered threatened locally, there is a general absence of narrow range endemic butterflies associated with mallee-heathland or mallee-woodland, possibly as a result of widespread land clearing practices of mallee vegetation in the past.


Soil Research ◽  
2018 ◽  
Vol 56 (8) ◽  
pp. 780 ◽  
Author(s):  
Mark Conyers ◽  
Beverley Orchard ◽  
Susan Orgill ◽  
Albert Oates ◽  
Graeme Poile ◽  
...  

Estimating the likely variance in soil organic carbon (OC) at the scale of farm fields or smaller monitoring areas is necessary for developing sampling protocols that allow temporal change to be detected. Given the relatively low anticipated soil OC sequestration rates (&lt;0.5 Mg/ha.0.30 m/year) for dryland agriculture it is important that sampling strategies are designed to reduce any cumulative errors associated with measuring soil OC. The first purpose of this study was to evaluate the spatial variation in soil OC and nitrogen (N), in soil layers to 1.50 m depth at two monitoring sites (Wagga Wagga and Yerong Creek, 0.5 ha each) in southern New South Wales, Australia, where crop and pasture rotations are practiced. Four variogram models were tested (linear, spherical, Gaussian and exponential); however, no single model dominated across sites or depths for OC or N. At both sites, the range was smallest in surface soil, and on a scale suggesting that sowing rows (stubble) may dominate the pattern of spatial dependence, whereas the longer ranges appeared to be associated with horizon boundaries. The second purpose of the study was to obtain an estimate of the population mean with 1%, 5% and 10% levels of precision using the calculated variance. The number of soil cores required for a 1% precision in estimation of the mean soil OC or N was impractical at most depths (&gt;500 per ha). About 30 soil cores per composite sample to 1.50 m depth, each core being at least 10 m apart, would ensure at least an average of 10% precision in the estimation of the mean soil OC at these two sites, which represent the agriculture of the region.


1988 ◽  
Vol 28 (1) ◽  
pp. 53 ◽  
Author(s):  
WH Johnston

The palatability of 20 accessions of E. curvula collected from naturalised populations in New South Wales was compared on 7 occasions with 2 selected accessions previously found to be highly palatable. The experiment was conducted at Wagga Wagga, N.S.W., between January 198 1 and July 1983. The relative palatability of most accessions was substantially similar from rating to rating, despite differences in the extent to which the trial was grazed. Palatability was related to the agronomic group to which the accessions belonged. For the naturalised taxa, Curvula was ranked equal to Tall Chloromelas. but both were more palatable than Short Chloromelas. The naturalised accessions were all less palatable than the selected accessions. It was concluded that the selected accessions were sufficiently palatable to be well utilised in pastures by stock grazing at commercial stocking rates.


1989 ◽  
Vol 29 (1) ◽  
pp. 51 ◽  
Author(s):  
DC McKenzie ◽  
HB So

The effect of gypsum on the properties and crop productivity of 6 contrasting vertisols of the Gwydir Valley, New South Wales was investigated in 1978 and 1979. These soils are often used for dryland wheat production, although crop growth is generally restricted by their structural instability. In 2 of the soils used in our study, the surface aggregates were sodic and dispersive (poor soils), 2 were relatively stable when wetted (good soils), whilst the other 2 soils had surface aggregates that were intermediate in behaviour (intermediate soils). The effects of added gypsum at 4 rates (0, 2.5, 5.0 and 7.5 t ha-1) on soil water profiles, soil properties and the growth of wheat were monitored over a 2 year period. Dryland wheat grain yields were increased by as much as 230% following the application of gypsum. Benefits were most pronounced on clays with sodic topsoils, a high water-holding capacity and adequate nutrition; plant response to gypsum on nearby soils with non-dispersive surfaces was less pronounced. Yield increases were associated with better seedling establishment, greater tiller production, increased grain weight, and lower incidence of 'Crown Rot' disease. Plant response to gypsum was related to improved water penetration into the soil, allowing greater storage of water in the subsoil, rather than loss via evaporation and possibly runoff. Increases as high as 137% in the soil water storage to a depth of 1.2 m were observed. Crop performance was also strongly influenced by rainfall, time of sowing and weed control. Where nitrogen and, to a lesser extent, phosphorus, were deficient in gypsum-treated soil, they had to be added before the extra soil water could be utilised effectively by wheat. On the lighter textured clays, gypsum appeared to aggravate nitrogen deficiency, apparently because of enhanced leaching.


2002 ◽  
Vol 42 (8) ◽  
pp. 1087 ◽  
Author(s):  
C. R. Kidd ◽  
G. M. Murray ◽  
J. E. Pratley ◽  
A. R. Leys

Winter cleaning is the removal of grasses from pasture using selective herbicides applied during winter. We compared the effectiveness of an early (June) and late (July) winter cleaning with an early spring herbicide fallow (September), spring (October) herbicide and no disturbance of the pasture on development of the root disease take-all in the subsequent wheat crop. Experiments were done at 5 sites in the eastern Riverina of New South Wales in 1990 and 1991. The winter clean treatments reduced soil inoculum of Gaeumannomyces graminis var. tritici (Ggt) compared with the other treatments at all sites as measured by a bioassay, with reductions from the undisturbed treatments of 52–79% over 5 sites. The winter clean treatments also significantly reduced the amount of take-all that developed in the subsequent wheat crop by between 52 and 83%. The early and late winter clean treatments increased the number of heads/m2 at 3 and 1 sites, respectively. Dry matter at anthesis was increased by the winter clean treatments at 3 sites. Grain yield was increased by the winter cleaning treatments over the other treatments at the 4 sites harvested, with yield increases of the early winter clean over the undisturbed treatment from 13 to 56%. The autumn bioassay of Ggt was positively correlated with spring take-all and negatively correlated with grain yield of the subsequent wheat crop at each site. However, there was a significant site and site × bioassay interaction so that the autumn bioassay could not be used to predict the amount of take-all that would develop.


Sign in / Sign up

Export Citation Format

Share Document